Google recently announced their new Project Tango Development Kit, a 7" tablet with a unique twist. At present this is a device for developers, scientists, and other research-oriented groups more than something for end users, but as with most Google projects the end goal is obviously to help create something that will end up being a useful addition to a retail product. You can read more about Project Tango, but the main point of interest is that the devices contain hardware and software that allows them to track and map 3D environments. Google states that the sensors make over a quarter million 3D measurements every second, updating its position and orientation in real-time.